Generally, the aluminum alloy billet utilized as machining materials, such as, for automobile parts and aluminum sash, is produced by casting molten aluminum alloy in the shape of rods, such as e.g., by DC casting, hot-top casting, hot-top gas pressure casting, and horizontal continuous casting, and then through long bar cutting process, homogenizing process, surfacing process, short bar cutting process, and defect inspection process.
Since ordinary DC casting makes it a rule to process in batch for every process the aluminum alloy billet is casted to a finite length, a long period of time is required until the final inspection. On that account, there is a drawback therein that it is prone to develop defective products, when a process failure occurs, and controlling at a low production rate so as not to break out any defective products lowers productivity. In contrast, the horizontal continuous casting obviates batch processing of the aluminum alloy billet in batch for every process, which is produced by continuously casting the molten aluminum alloy in the shape of rod. This enables manufacturing of the aluminum alloy billet without a decrease in the productivity.
Incidentally, the aluminum alloy billet yielded by casting the molten aluminum alloy might develop defects including a casting defect depending on the casting condition. Thus, for the aluminum alloy billet produced by casting the molten aluminum alloy to be cut into a predetermined length for shipment as a product, it is necessary to inspect the product for a defect in the aluminum alloy billet to control the quality thereof. Hereupon, as techniques of controlling the quality of the aluminum alloy billet produced by continuously casting the molten aluminum alloy are widely known. One of the techniques is that a surface and the inside of the aluminum alloy billet undergo a nondestructive inspection and the quality of the aluminum alloy billet is controlled based on the inspection results. Another technique is that an ultrasonic flaw inspection is conducted to the aluminum alloy billet pulled out from the mold of the continuous casting device for control of the quality of the aluminum alloy billet.
Further, in the technique in which the billet is directly cut into a length of the product after being casted to the shape of a billet, there has thus far been no art of the management of production and inspection information or the feedback thereof to the manufacturing process.